GENOME-WIDE ASSOCIATION STUDY (GWA STUDY, OR GWAS) • a/k/a whole genome association study (WGA study, or WGAS) • most common approach of GWA studies is the “case-control setup” which compares two large groups of individuals • It finds out associations between single-nucleotide polymorphisms (SNPs) and major diseases. • Used to identify biological pathways; networks underlying complex diseases and in drug development process. • Normally compare the DNA of two groups of participant i.e.people with disease (cases) and without disease (controls). • It can detect significantly “ALTERED ALLELE FREQUENCY” when comparing with healthy controls • Each person gives DNA-sample; from which millions of genetic variants are read using SNP arrays. If one type of variant (one allele) is more frequent in people with the disease, the SNP is said to be "associated" with the disease. • associated SNPs are considered to mark a region of human genome which influences risk of disease. • GWA studies investigate entire genome.